Polymer based microspheres of aceclofenac as sustained release parenterals for prolonged anti-inflammatory effect

Abstract

Poly(lactic-co-glycolic acid) (PLGA) (75:25) and polycaprolactone (PCL) microspheres were fabricated for prolonged release of aceclofenac by parenteral administration. Microspheres encapsulating aceclofenac were designed to release the drug at controlled rate for around one month. Biodegradable microspheres were prepared by solvent emulsification evaporation method in different polymer:drug ratios (1:1, 2:1 and 3:1). After drug loading, PLGA and PCL microspheres showed a controlled size distribution with an average size of 11.75μm and 3.81μm respectively and entrapment efficiency in the range of 90±0.72% to 91.06±4.01% with PLGA and 83.01±2.13% to 90.4±2.11% with PCL. Scanning electron microscopy has confirmed good spherical structures of microspheres. The percent yield of biodegradable polymeric microspheres ranged between 30.95±10.14% to 92.84±3.15% and 47.33±4.72% to 80±3.60% for PLGA and PCL microspheres respectively. PLGA microspheres followed Higuchi release pattern while Korsmeyer-Peppas explained the release pattern of PCL microspheres. Stability studies of microspheres were also carried out by storing the preparations at 2-8°C for 30, 60 and 90days and evaluating them for entrapment efficiency, residual drug content and polymer drug compatability. In-vivo studies showed significant anti-inflammatory activity of microspheres upto 48hours using the carrageenan induced rat paw oedema model.